[ntp:questions] National time standard differences

Richard B. Gilbert rgilbert88 at comcast.net
Tue Feb 9 15:07:38 UTC 2010


David J Taylor wrote:
>> I've setup an NTP server in the south east asia region synchonising
>> with regional NTP servers as well as a couple of servers I am
>> responsible for in the US.
>>
>> remote        st t when poll reach   delay   offset  jitter
>> ==============================================
>> +Japan         1 u  454 1024  377   87.402   -0.560   0.056
>> *Japan         1 u  476 1024  377   87.277   -0.810   1.542
>> -NorthAmerica  2 u  427 1024  377  285.387  -17.741   5.084
>> -NorthAmerica  2 u  429 1024  377  307.208  -17.061   0.083
>>
>> Is the above delta seen between Japanese and North American time
>> sources purely the delta between the outbound / return network path or
>> something else?
>>
>> Chris
> 
> Chris,
> 
> Most likely asymmetrical paths, yes.  To answer your implied question, 
> it is most /unlikely/ that the USA National Time is 17 milliseconds away 
> from Japan National Time, if that's what you were thinking.  National 
> time differences are likely to be microseconds or less, I believe.
> 

I believe that the word "less" is appropriate here but might be called 
an understatement.  I'd guess that the various national time standards 
are within nanoseconds or less.




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